Perhaps you should try some spelling variations:
than quoc » tran quoc, toan quoc, phan quoc
cua triet » cua viet, su triet, va triet
sach thi » sach thu, sach tai, sach thieu
thi hang » thi hanh, thi nang, thi hong
hang mai » hoang mai, hang tai, hang hai
mai khoi » mai khoa, tai khoa, cac khoi
thanh vi » hanh vi, thanh va, thanh ve
su sach » so sach, vu sach
vi cua » vai cua, di cua
gia » giao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach thi hang mai khoi. hieu qua ((than quoc) or (han quoc)) gia thanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi hang mai khoi. hieu qua ((than quoc) OR (han quoc)) gia thanh vi cua triet.
• Adding a wildcard symbol may retrieve word variants: su sach thi hang mai khoi. hieu qua ((than quoc) or (han quoc)) gia thanh vi cua triet*.